Hydroxycitric Acid has been known for many years to be beneficial for the control and reduction of mammalian body weight. In particular, a specific stereoisomer of hydroxycitric acid, the (−)hydroxycitric acid isomer and derivatives thereof, is known to inhibit fatty acid and cholesterol synthesis and to function as a natural anorectic agent in mammals.
The stereoisomers of hydroxycitric acid are related structurally to citric acid wherein a hydroxy group is substituted for one of the four methylene hydrogens. Thus, there are four possible stereoisomers of hydroxycitric acid. Of these four stereoisomers, the (−) hydroxycitric acid isomer has been found to substantially inhibit fatty acid synthesis in biological systems in profused organs and intact mammals, and particularly in non-ruminant mammals.
It has also been known that the particular stereoisomer of interest, in both free acid and lactone forms, is found in the rind of the fruits of Garcinia species, for example, Garcinia cambogia, Garcinia atroviridis and Garcinia indica, which are native to the Indian subcontinent. The hydroxycitric acid component can be obtained by isolation from the fruit of Garcinia species using known procedures, for example Lewis, Y. S. “Methods in Enzymology” (J. M. Lowenstein, Ed., Vol. 13, pg. 613) (Academic Press, N.Y. 1969), and U.S. Pat. No. 5,536,516.
As an inhibitor of the synthesis of fatty acids and cholesterol, hydroxycitric acid has been shown to significantly reduce the body weight and lower lipid accumulation in rats. See, e.g. Sergio, W. Medical Hypothesis 27:39 (1988), Sullivan, A. C., et al., Lipids 9:121 (1973), and Sullivan, A. C., et al., Lipids 9:129 (1973).
However, in order to formulate the compositions containing hydroxycitric acid into dietary supplements and food products, a number of desirable properties are sought. First, as most such supplements and food products are administered orally, the composition should have negligible odor and taste. Second, in order to increase the bioavailability of the hydroxycitric acid, the composition should be soluble in water. Solubility in water, as well as clarity in solution, are also important properties in many food and beverage applications. In addition, it is highly desirable that the composition be non-hygroscopic, in order to facilitate storage and formulation into dietary supplements and food products. Another desirable property is the hydroxycitric acid potency of the composition, where high potency levels are desirable.